Macklem P T, Gross D, Grassino G A, Roussos C
J Appl Physiol Respir Environ Exerc Physiol. 1978 Feb;44(2):200-8. doi: 10.1152/jappl.1978.44.2.200.
We tested the hypothesis that the inspiratory pressure swings across the rib-cage pathway are the sum of transdiaphragmatic pressure (Pdi) and the pressures developed by the intercostal/accessory muscles (Pic). If correct, Pic can only contribute to lowering pleural pressure (Ppl), to the extent that it lowers abdominal pressure (Pab). To test this we measured Pab and Ppl during during Mueller maneuvers in which deltaPab = 0. Because there was no outward displacement of the rib cage, Pic must have contributed to deltaPpl, as did Pdi. Under these conditions the total pressure developed by the inspiratory muscles across the rib-cage pathway was less than Pdi + Pic. Therefore, we rejected the hypothesis. A plot of Pab vs. Ppl during relaxation allows partitioning of the diaphragmatic and intercostal/accessory muscle contributions to inspiratory pressure swings. The analysis indicates that the diaphragm can act both as a fixator, preventing transmission of Ppl to the abdomen and as an agonist. When abdominal muscles remain relaxed it only assumes the latter role to the extent that Pab increases.
胸廓通道上的吸气压力波动是跨膈压（Pdi）与肋间肌/辅助肌产生的压力（Pic）之和。如果该假设正确，那么Pic只能在降低腹压（Pab）的程度上，对降低胸膜腔压力（Ppl）起作用。为了验证这一点，我们在米勒动作过程中测量了Pab和Ppl，此时ΔPab = 0。由于胸廓没有向外移位，Pic必定和Pdi一样，对ΔPpl有贡献。在这些条件下，吸气肌在胸廓通道上产生的总压力小于Pdi + Pic。因此，我们拒绝了该假设。在放松过程中绘制Pab与Ppl的关系图，可以区分膈肌和肋间肌/辅助肌对吸气压力波动的贡献。分析表明，膈肌既可以作为固定器，防止Ppl传递至腹部，也可以作为主动肌。当腹部肌肉保持放松时，它仅在Pab增加的程度上承担后一种角色。
